Electric air heater



March 30,1926. 1,578,897

CARL-OLOV LINDBERG ELECTRI 0 AIR HEATER Filed June 11, 1924 Patented Mar. 30, 1925.

UNITED STATES CARL-OLOV LINDBERG, OF STOCKHOLM. SVEDEN.

ELECTRIC AIR HEATER.

Application filed June 11, 1224. Serial No. 719,328.

To all whom it 912 try concern:

Be it known that I, CAnL-OLov Lrnnnnno, a citizen of the Kingdom of Sweden, residing at Stockholm, Sweden, have inventednew and useful Improved Electric Air Heaters, of which the following is a specification.

This invention relates to electric airheaters, and more particularly to air-heaters for use in connection with explosive engines using gasolene or a similar light fluid as the motive power, to supply the carburetor with heated air, with the object in view to facilitate starting in cold weather or prevent the carbureter from being burnt up due to return explosions from the engines.

The object of this invention is to provide an air-heater of the said kind which permits of proper adjustment of the passage of air through the heater in a simple and efficient way, and further permits an automatic adjustment of the air with change in electric current.

In the accompanying drawingan embodi' ment of the invention is illustrated.

Figure 1 is a longitudinal section through the air-heater proper; Fig. 2 is a front elevation of a valve belonging to the heater; and Fig. 3 is a longitudinal section through a common controlling mechanism for said valve and for the electric current.

The air-heater comprises a tube 1, Fig. 1, adapted to be attached to the air-intake pipe 2 of the carburetor of an explosive engine using gasolene or a similar fuel as the motive power. Inserted in said tube is an electric heating coil 3 and a valve or damper 4:.

The tube may preferably be coated on its inner surface with a heat-insulating material, such as asbestos. The heating-coil 3 comprises a suitable wire or tape wound as a cone the largest diameter of which corresponds to the inside diameter of tube 1. The coil is carried by two pins 5, 6 secured to the wall of tube 1, which serve at the same time as binding posts.

Due to the fact that the coil is freely suspended, the heat thereof will be transmitted directly and instantaneously to the air passing through the tube 1, and the conical shape of the coil will secure auniform heating of said air, while preventing the various turns of the coil from coming into contact with one another due to vibrations of the engine or vehicle.

The valve 4: is adapted to be kept closed when the engine is to be started. This will prevent the air first heated by the coil from escaping into the atmosphere before the engine has reached a certain speed and the suction of air by the engine is initiated. The valve 4 may yet be formed with radially extending apertures 7 allowing a restricted amount of air to pass even in the closed condition of the valve. The plate 4; may be adiusted in different positions to vary the airpassage through the tube. As soon as the engine has been started the valve should be completely opened. The movement of the valve may be controlled by a spring operated handle 8.

The means for controlling the valve may, preferably, be combined with an interrupter controlling the supply of current to the coil 3 so that the closure of the electric circuit and the closure of the valve may be effected by one and the same manipulation. Sucha combined controlling mechanism is shown in the drawing. Attached to the valve shaft 11 is a lever 12 which in the open condition of the valve is in the position shown by dotted lines 12 'The valve may be closed by pulling at the button 8 the stem 9 of which is connected to the lever 12 by a Bowden cable 10.

Figs. 1 and 3 show the position of the valve and the lever 12 when the button 8 is pulled out. The button, when released, is restored automatically to its innermost position and causes thereby the valve to close. This is due to the effect of thesprings 13 and 14. The stem 9 of the button 8 carries a contact clip 15 cooperating with two metal plates 16 serving as contact surfaces which are carried inside a sleeve 18 by means of suitable insulating blocks 1?. The closure of the electric circuit is effected by the clip 15 which is caused due to a pull at the buttoii 8 to move upwards into between the disks 1G to the position shown by full lines in Figs. 3. The current may then pass from the two metal plates 16 to the clip 15. The plates are connected to each other by a conductor (not shown and are further connected, by the conductor 20 to the binding post 21 connected to one terminal of a hcat--' ing battery (not shown) the other terminal of which is connected to one of the pins 5, 6. The other pin is connected, as by the engine frame, to the sleeve 18, the clip 15 being electrically connected to the engine frame by way of the spring 13 and the button stem 9. Immediately upon the release of the button 8, the contact clip 15 will be restored to its normal position (as shown by dotted lines 15 under the action of its spring 13. The circuit is now open.

The contact plates 16 are carried by a disk or the like 22 and insulated therefrom by an insulating member 23. The disk 2-2 is adapted to he attached to an ap nopriate part 2i ot the vehicle.

,ciir passing tl'irough the tuhe 1 is heated by the coil 3 and. due to the conical :loru'i of the coil said heating will take place unitornily over the entire area of the tube. The heated air enteringthe carburetor n l] ena-hl'e the starting to he eiiected easil'y andv instantaneeusly even in cold weather and with. the use elf a relatively heavy fuel as the motive power.

This will remove a plurality. of heavy incaimveniences; inherent to vain starting attempts. Thus, the lubricating oil will never he mixed with fuel which, as a result of such *ain starting attempts, will escape in nonvaporized state from the carhuret'er to he thereafter drawn into the cylinders {11K frem thence beyond the pistons down into the crank casing. The starting storage hattery will he freed from the over loading to which it is subjected when it has to supply an engine which is heavy to start due to had vaporization of the fuel, with current during; a longer period.

As a result of the immediate starting of the engine the liability of the starting inctor to he prematurely worn out or hurnt will be dispensed with. Furthern'iore, it is to he noted that the heating coil forms a good explosion guard which may he further improved by inserting a wire net below the coil.

It is further to be noted that modifications may he made without departing from the principle of the invention. For instance, the coil 3 mayhave a different form from that shown, as the form of a flat coil. In such case, however, the danger of shortcircuit between the various turns is considerably increased and the total length of the coil considerably reduced.

When applying the heater to engines having no electric starting machinery, the interrugter i'uay, preferably, be provided with lockingn'ieuns permitting the current to re main closed even after the button 8 is released.

Wh'at 1 claim is: I

In an air-heater 't'or explosive engines. a tithe, a damper in'said tube adapted to control the. llow otair therethrough, an electric heating coil in. said 'tu e, a manually operable switch adapted to control the circuit of said coil and mechanical connection hetwee'n said switch and said damper adapted to close the damper at the opening of said circuit.

In testimony whereof I have signed my name.

CARL-QLOV LIIlDl'SER-G. 

